1. Field of the Invention
This invention pertains to an apparatus for collecting and storing a sample of an environmental gas such as air. Each day man is becoming more and more concerned with his environment and particularly the air he breathes. In order to monitor the quality of the air, air sampling devices are utilized to draw in a quantity of the air which is confined to a storage receptacle and subsequently withdrawn form the storage receptacle in the laboratory where it can be checked for noxious and toxic elements by means of a gas analyzer.
2. Description of the Prior Art
The present invention is an improvement of the device disclosed in U.S. Patent Application Ser. No. 956,312, filed Oct. 31, 1978, now U.S. Pat. No. 4,195,524 drawn to a "Method and Apparatus for Collecting and Storing Environmental Gases". In the device of the application a sample bottle is cooled by means of a cryogenic refrigerator to create a partial vacuum within the sample bottle so that an air sample can be drawn through a metering orifice (valve) into the sample bottle where it is condensed and refrigerated until the bottle is full. After the bottle is full the entire apparatus is taken to the laboratory where the sample bottle can be warmed and the sample withdrawn for analysis. The cryogenic refrigerator being fixed to the bottle necessitates the entire apparatus being taken to the laboratory.
The device of the patent application was an improvement over the most common method of sampling environmental gases which consists of utilizing a conventional compressor to force the environmental gas under pressure into a sample container. One of the problems associated with the compressor method of forcing an environmental gas sample into a container is the fact that the sample could become contaminated due to the use of oils or other lubricants in the compressor.